1. Field of the Invention
The present invention relates to a substrate with a microstructure and method for producing the same, and particularly, a substrate with a microstructure and method for producing the same by using a non-aqueous self-assembly process.
2. Description of the Related Art
Self-assembly is a microscopic phenomenon existed in nature. This begins with the permeation of a plurality of micro-/nano-particles into an aqueous solution. Evaporation of the solution will cause the liquid level of the aqueous solution to lower down, thus the mutually interactive forces of the particles force them to aggregate and align with each other. This is the self-assembly happened naturally.
Generally speaking, nano scale particles are traditionally used in research and manufacturing, then the self-assembly structure is reproduced to obtain the required inverse mold. Furthermore, surface modification of the substrate and controlling environmental humidity are necessary to obtain a better particle adhesion and a monolayer self-assembly structure. In other words, implementing this manufacturing process will increase the cost expense.
There are other methodologies of manufacturing microstructures. For example, Taiwan invention patent (Publication Number: 200817778) discloses a partially immersed monolayer particles, wherein an aqueous adhesive is mixed with colloidal particles to perform the self-assembly process and to form a structure membrane. Furthermore, controlling the liquid evaporation self-assembly is required in this patent (forming the substrate and the monolayer structure through water in a humid environment). Besides, the constant-diameter microparticles are polymer particles with the diameter between 1-20 μm. Moreover, the generated membrane includes the physically monolayer arranged particles partially immersed in the adhesive. The drawback of this process is that it is required to control the liquid evaporation speed to reach the self-assembly purpose. However, this is not easy to achieve in practical implementation. Besides, the requirement of the constant-diameter microparticles is expensive in cost.
Additionally, the Taiwanese patent (Patent Number: I221826) discloses a mold manufacturing method by utilizing a chemical self-assembly process. This method mainly relies on the chemical self-assembly process to form a self-assembled monolayer (SAM) membrane on a substrate, then disposes a particle-containing solution over the chemical membrane to form a particle layer with a specific arrangement. Afterwards, this particle layer is used as a master mold to manufacture molds by electroforming. Besides, the surface of the substrate is processed and able to form chemical bonds with bifunctional group molecules, then perform the electroforming after the allocation of the self-assembly particles. However, the drawback of this method is that a chemical layer must be generated on the surface of the substrate in advance to activate the self-assembly with the particles. This manufacturing process is complex, time-consuming, and expensive.
Additionally, the Taiwanese patent (Patent Number: I315321) discloses a lens array manufacturing method, a lens array, and its optical device array apparatus. First, a self-assembled monolayer is generated on a substrate to form a hydrophilic area and a hydrophobic area. Afterwards, a liquid material is spread on the substrate to generate a plurality of liquid lenses on the hydrophilic area, then the plurality of liquid lenses are cured to form the lens array. However, the drawback of this method is a hydrophilic area and a hydrophobic area must be generated in advance on the surface of the substrate, such that liquid lenses can be generated on the hydrophilic area and solidified. This manufacturing process is complex, time-consuming, and expensive.